The United States Post Office (USPO) has been considering electronic postage stamps for several years. According to the USPO, electronic postage should be printed on an envelope in the upper right hand corner (or on a label for an envelope or package), convey evidence that postage has been paid, contain mail processing data requirements, and contain security-related data elements. As shown in FIG. 1, the USPO desires that an electronic postage stamp be made up of human readable information as well as a two dimensional barcode with the following information: Licensing ZIP Code Date of Mailing Destination Delivery Point Postage Software ID Digital Signature Ascending Register Rate Category Descending Register Reserve Field Algorithm ID Indicia Version Number Device ID Certificate Serial Number.
There are presently several competing commercial schemes for electronic postage. Typically these schemes are based on digital certificates. One such scheme provides a way for the postal vendor to access a secure nonvolatile memory on a user's computer with a postage printing program. The goal here is to control the printer so that it never prints a given certificate twice, i.e., never prints the same certificate onto more than one copy of a label or envelope. Yet another scheme uses a unique mail piece identifier generated by a trusted third party for encrypting the postage information. The encrypted information is then printed on the mail piece. The problem with such methods is that because certificate information can be easily photocopied, the goal of security is not achieved. Unless the certificates are checked for re-use with an expensive database lookup system, there is no reliable way to prevent the certificate information from being copied and reused illicitly. Thus, none of the competing schemes provide a way to fully authenticate the electronic transactions generating the electronic stamps. Without adequate protection against copying, tremendous amounts of revenue are at risk.
Another problem with current schemes is that they typically do not provide an easy mechanism for revocation and replacement of electronic stamps in the case that an envelope tears or the printer jams. In advertent failure to mail a stamped article on the date encoded in the e-stamp certificate results in a similar problem—how can the user avoid forfeiting the money spent to purchase the postage? Some current schemes provide limited functionality for redating or otherwise correcting e-postage, but current techniques are typically clumsy and inefficient, which is particularly costly when one considers that postage stamps are used in extremely heavy volume.
The same needs and problems apply more generally to information-based indicia (“IBI”) for transactions besides postage, such as facility admission tickets (for events, movies, travel, etc.), coupons, vouchers, certificates, visas, receipts, and checks.